Functional polymers such as ion exchange resin, chelete resin and the like have been widely used as carriers for various chemical substances, heretofore. These functional polymers generally have various reactive groups (for example, active hydrogen-containing groups, such as carboxyl groups, hydroxyl groups and primary or secondary amino groups) on their surface.
Recently, it has been also proposed to fix a biologically active substance (e.g. drug, enzyme, etc.) to the functional polymer to convey it to a focus. In such the application, it is necessary that a functional polymer carrier carries a predetermined amount of drugs, uniformly and securely. Further, it is also necessary that the functional polymer has good dispersibility to various solvents. In general, when the functional polymer is used as a carrier for drugs, it is preferred to use those having primary or secondary amino groups which have a variety of reactivity to form a stable bond with various functional groups.
Accordingly, in order to securely carry the drug, it is preferred that the functional polymer has primary or secondary amino groups. Further, it is possible to control an amount of the drug to be carried and dispersibility to various solvents by changing a particle size of the functional polymer to modify a surface area of the polymer. However, in order to obtain good solvent dispersibility, the particle size of the functional microparticle must be uniformly adjusted to about 10.mu. or less.
The uniform functional polymer microparticle having good carrying property can also be used as chromatographic carriers, viscosity modifiers, resin molding materials, paint additives, crosslinking agents, curing agents and cosmetic additives, in addition to the application as the above pharmaceutical carriers and, therefore, demand for the polymer is increasing.
The organic polymer particles having primary or secondary amino groups are known. For example, in Japanese Patent Kokai No. 60-90243, there is described a process for producing particles by internally crosslinking an aqueous polyallylamine solution. However, in this process, it is difficult to control a particle size of the particle to be obtained and no particle having a particle size of about no more than 10.mu. can be obtained.